Sewing machine needle



1957 R. H. LUKINS SEWING MACHINE NEEDLE 5 Sheets-Sheet 1 Filed May 24, 1965 NQQ 06L 1967 R. H. LUKINS SEWING MACHINE NEEDLE 3 Sheets-Sheet 2 Filed May 24. 1965 Oct. 17, R. H. LUKINS SEWING MACHINE NEEDLE Filed May 24, 1965 3 Sheets-Sheet 3 United States Patent T 3,347,192 SEWING MACHINE NEEDLE Richard H. Lukins, Glen Ellyn, Ill., assignor to Union Special Machine Company, Chicago, Ill., a corporation of Illinois Filed May 24, 1965, Ser. No. 458,322 9 Claims. (Cl. 112-222) ABSTRACT OF THE DISCLOSURE A sewing machine needle in which the blade portion, intermediate the point and shank, has a cross-section increasing in area from the point end to the shank, the sides of the blade portion being fiat and lying in parallel planes and being gradually wider in a direction toward the shank end.

This invention relates to sewing machine needles. More particularly, it relates to a sewing machine needle which is preferably, although not necessarily, curved and which has a leading end portion conically shaped and which terminates in a sharp point at the leading end of the needle, a shank at its butt end to be clamped in the needle carrier of a sewing machine and a blade portion leading into and connected to said conical end portion at its leading end and connected to the shank portion at its trailing end, the blade being tapered so that its cross sectional area normal to the long axis of the needle is less at its leading end than at its trailing end, the blade being shaped to have oppositely disposed elongate flat portions along its sides.

Needles made according to the invention are admirably suited for use in sewing machines wherein curved needles are required. An example of such a sewing machine is disclosed in Hayes US. Patent No. 3,101,686 entitled Machine for Producing Safety Stitch. This is but one example of sewing machines wherein curved needles are used and it will be understood by those skilled in the art that there are various other types of sewing machines wherein curved needles made according to this invention may be used.

' Needles heretofore available for use in a machine such, for. example, as the one shown in the above mentioned patent, have drawbacks which are overcome by the present invention. Needles heretofore available, especially curved needles, when used in a sewing machine which operates at high speed, having a tendency to and often do, vibrate and flutter excessively, and it is quite difficult to control the needle point which reciprocates at high speed during a stitching operation. The vibration and flutter of the needle make it almost impossible to control the penetration of the needle point into the'fabric at the same point with respect to each stitch in successive stitches along the line of stitching. The vibrations and flutters are caused by the bending of the needle at impact as the point of they needle strikes the fabric in successive strokes as the stitching proceeds. In some instances, the erratic movement of the needle has caused the point to strike the machine throat plate alongside of the needle hole, the top of the looper or the needle guards and this has resulted in poor sewing and, in addition, an excessive needle breakage. Furthermore, the size of the needle must be kept within rather narrow limits to 'avoid a needle puncture into the fabric which would be so' large as 'to result in an unwanted and unsightly appearance.

It has been an object of this invention to provide a sewing machine needle that eliminates, or at least avoids to maximum extent, the unwanted vibration and flutter characteristic of the heretofore available curved needles of comparable size. v

' This object has been achieved by making needles in a manner, hereinafter described in detail, so that they are after it is formed to final shape;

3,347,192 Patented Oct. 17, 1 967 materially stiffer than needles of comparable standard sizes heretofore available.

According to the invention the improved needle comprises an end portion of generally conical shape having a sharp point at the leading end of the needle, a shank portion at the butt or trailing end of the needle, and a blade portion intermediate the conically shaped leading end portion and the shank portion; the blade portion having an eye at its leading end and a thread groove along the top side of the needle, and, if desired, a thread groove on the under side of the needle, the sides of the needle having elongate flat surfaces and the cross sectional area of the blade normal to its long axis being larger at its trailing end than at its leading end According to a preferred embodiment of the invention, the elongate flat surfaces of the blade lie in spaced parallel relation throughout their entire length from the eye to the shank of the needle and the needle is curved to the desired radius of curvature to meet the requirements for use in sewing machines employing curved needles.

To provide a frame of reference and for convenience of description, the curved needle may be thought of in terms used in the bow and arrow art, it being common terminology in that art to refer to the string side of the bow as the belly and the other side of the bow as the back. With that frame of reference in mind, the belly side of the curved needle is herein referred to as the concave or bottom side of the needle and the back, as the convex or top side of the needle.

With the foregoing objects, features and advantages of the invention in view, a preferred embodiment and certain modifications thereof, and the manner of producing the same, will now be described in further detail by reference to the accompanying drawings in which:

FIG. 1 is a view in elevation of a blank having a tapered blade portion from which the needle of the invention is formed;

FIGS. 2 and 3 are views in cross section respectively on lines 22 and 33 of FIG. 1, to larger scale;

FIG. 4 is a top plan view of the blank shown in FIG. 1, after subjecting it to a coining'or stamping operation to form fiat sides along the blank;

FIGS. 5 and 6 are views in cross section respectively on lines 5-5 and 66 of FIG. 4, to larger scale;

FIG. 7 is a side view in elevation of the blank shown in FIG. 4;

FIGS. 8 and 9 are views in cross section respectively on lines 8-8 and 9-9 of FIG. 7, to larger scale;

FIG. 10 is a top plan view of the needle after the eye and thread grooves are formed;

FIG. 11 is a side view partly in section on line 1111 of FIG. 10;

FIGS. 12, 13, 14 and 15 are views in cross section respectively on lines 1212, 1313, 1414, and 15-15 ofFIG.11; I I I 1 FIG. 16 is a side view in elevation of the curved needle FIG. 17 is a side view of a needle in straight form similar to FIGS. 10 and 11 but without a thread groove on the under side; partly in elevation and partly in section;

FIG. 18 is a side view in elevation of the needle shown in FIG. 17;

FIG. 19 is a View of a needle like FIGS. 17 and 18 after it has been shaped to curved form; and

FIG. 20 is a view in cross section on line 2020 of FIG. 19.

Referring now to the drawings in which like reference characters indicate similar parts throughout the several views, a blank 10 (FIG. 1) is provided which is to be made into its final preferred curved form 11 as shown in FIG. 16. The blank 10 (FIG. 1) comprises a tapered piece of suitable material, such as steel, circular in cross section throughout its length and increasing in cross-sectional area toward the shank. More particularly, the blank .10 comprises a conically shaped leading end portion 12 which terminates at its leading end in a sharp point 13; a blade portion 14 which at its leading end is the same diameter as the base end 15 of the cone portion 12 and becomes gradually larger in cross section in the direction toward the butt or trailing end 16 of the blank. The larger trailing end 17 of the blade portion joins with the shank 18; the shank having a tapered portion 19 at its leading end. This tapered portion 19 merges into the rear end portion 20 of the shank which is cylindrical in shape and of a size to fit into the reciprocating needle carrier of the sewing machine.

Although needles of different sizes comparable to standard sizes of sewing machine needles may be made according to the invention, a size as shown in the drawings to a much larger scale than the actual physical needle will be described for purposes of illustrating the features which characterize the invention. It may be assumed that the actual blank, as illustrated in FIG. 1, is .040" in diameter at the base 15 of the cone portion 12 and the diameter of the blank at 22 of FIG. 1 is .048". The cylindrical portion 20 of the shank may have a diameter of .079 and a suitable length of say .6. The overall length of the needle blank from the end 16 to point 13 may be taken to be 1.774"; it being understood of course that the invention lends itself to the production of longer or shorter needles and also needles whose blade portions are greater or smaller in diameter than the particular diameters mentioned above; the significant point here being that the blade portion of the blank tapers and becomes larger in the direction of the trailing end.

To shape the blank toward the ultimate form the finished needle is to have, the blank 10 is subjected to a coining or stamping operation to form flat sides along the length of the blade portion. This may be accomplished, for example, by coiningthe blade portion of the blank, between .a pair of oppositely disposed flat dies, which exert metal deforming forces toward each other, thereby causing the metal adjacent the die surfaces to flow in a manner that two oppositely disposed fiat sides 22 and 23 are formed on the sides of the blade portion of the blank and at the same time the metal at the top side 24 and the bottom side 25 is caused to flow so that the periphery of the blade is changed from circular shape, as shown in FIG. 1, to ovaloid shape as illustrated at 24, 25, 24a, 25a, in FIGS. 5, 6, 8 and 9; the initial shape being illustrated in broken lines in those figures. The oppositely disposed flats 22, 23 lie in parallel planes and, as illustrated, the width W between the flats along their length is ..040" in the physical needle as illustrated in .the drawings. The deformation of the metal thathas taken place as the result of forging the blank to form the vertical side flats 22,23, may be observed by comparing FIG. 2 with FIG. 8 and FIG. 3 with FIG. 9. The diameter of the blank .10 on line 2-2, as shown in FIG. 2, is .048". The outline of FIG. 2 is shown in FIG. 8 in broken lines. By coining the fiat sides 22, 23, the metal has been caused to flow so that the peripheral surface in the areas of the top side 24 and the bottom side 25 (see FIG. 8) between the flats 22, 23 is'ovaloid in shape. The vertical height h (see FIG. 8) of the blank 10a on line 88 of FIG. 7 is .051", which is greater than the diameter .048" of the initial blank 10 (FIG. 1); it being noted that FIGS. 2 and 8 are taken at the same distance from the butt end, i.e., on lines 22 of FIG. 1 and 88 of FIG. 7. Of course, there is less deformation of the metal at the top side and bottom side at the leading end portion of the blade portion 14 of the blank (see 24a, 25a, FIG. 9) because the flats 22, 23 are in parallel planes and the blank to begin with at line 3-3 has a diameter only very slightly greater than .040" since the diameter of the blank at the base of the cone portion 12 is .040". Also, it will be observed that the width wt of the flats 22, 23 at their trailing ends ,is greater than the width wl at their leading ends, the leading ends of the flats merging into the circular peripheral surface of the blade portion 14 at its leading end. That is, the edges 22c and 22 of flat 22 converge in a direction toward the leading end. Likewise, edges 23:: and 23f of flat 23 converge toward the leading end. By subjecting the blank to metal forming dies as mentioned, the blade portion of the .needle blank (now designated by reference numeral 10a) is in effect made nar-. rower in width without sacrifice or loss of metal since the metal is caused to flow in a manner to cause the blade to be thicker (in vertical direction h as shown in FIG. 8) than it was initially (asshown in FIG. 2).

The blank 10a is then subjected to milling and drilling operations to form a thread groove 28 along the top side of the blank, a thread groove 29. on the bottom side of the blank and an eye 30 through the blade at its leading end, and a flat surface 31 along the lengthof the shank 20; as shown in FIGS. 10 to 15, the blank now being designated by reference numeral 10b. The shank flat 31 lies in a plane parallel with a vertical plane through the long axis of the blank 10b and therefore in a plane parallel with the,

flats 22, 23 and it serves as a base which is engaged by a set screw on the needle carrier so that the needle may be clamped tightly and in aligned position in the needle carrier.

The constant widthtop thread groove 28, as shown in FIG. 11, has a flat bottom 32 and at its trailing end the bottom has an inclined portion 33 which curves upwardly and feathers out at 33a in the shank portion. The leading end portion of the thread groove 28 has an inclined portion 34 which curves upwardly in a direction toward the point of the needle, beginning at a point at the forward end of the eye 30 and feathers out at 34a in the cone shaped portion 12. The bottom 32 of groove 28 between the upwardly inclined portions 33 and 34 is flat. A groove 39 is provided on the underside of the blade portion which extends longitudinally across the eye opening 30, which opening is bounded by curved front and rear walls 40 and 41 and side walls 42 and 43. A constant width thread groove 29 similar to groove 28 is provided on the underside of the blade extending to the recessed portion 26 in the bottom side ofthe blade. It has inclined curved portion 46 which merges with the underside surface of the blade. The depths of grooves 28 and 29 are such, in the illustrated embodiment, as to provide between them a web portion 44 (see FIG. 13) having a height hf or thickness which is substantially greater than prior art sewing I machine needles of comparable size and type. The underside of the blade has the cut-out or recessed portion 26 on the underside of the blade. It is of constant radius intermediate the grooves 29 and 39, a typical cross section taken on line 14--14, being shown in FIG. 14.

The blank now designated as 10b is then shaped to final desired curved form as illustrated in FIG. 16, which is a side view in elevation of the final shape of the needle. It will be understood, of course, that the radius of-curvature of the blade will be selected vto suit the curvature required for proper operation in the sewing machine in which it is intended to be used.

The needle illustrated in FIG. 19 is similar in all respects to that illustrated in FIG. 16 except that there is no thread groove in the bottom side of the blade corresponding'to groove 29; the needle being shown in straight form in FIG. 11 prior to shaping it to curved form, its final curved form being shown in FIG. 19.

It will be seen from the foregoing description that needles may be constructed according to the invention in to the invention which are thirty-eight percent stiffer than the prior art needles of comparable size.

It will be seen from the foregoing description that the ovality of the blade portion increases in depth from the leading end to the trailing end. This has the advantage that it increases the rigidity of the needle when under a stress which causes deflection along a plane parallel to the coined fiat sides. Since the needle is supported by a needle holder in somewhat the same manner as a cantilever beam, application of a force on the needle point will cause deflection in which the bending moment increases toward the shank of the needle. The resistance to the bending moment in a beam of cantilever suspension is proportional to the third power of the depth or thickness of the cross section of the beam. Therefore, if the depth or thickness of the cross section of the beam and, similarly, of the needle is increased toward the support end, the degree of deflection will be significantly reduced in comparison to a beam or needle of uniform section.

Also it should be noted that, in increasing the thickness of the blade, this has been done without increasing the width. Hence, when the needle punches the fabric in a stitching operation, it does not make a needle puncture in the fabric in a direction transverse to a plane drawn through the axis of the needle. The needle puncture is enlarged only in a plane parallel with the direction of feed. Since the needle puncture is enlarged only in the direction of feed, it will be covered by the needle thread on top of the fabric and by the looper thread on the bottom side of the fabric, and therefore not visible.

The terms and expressions which have been employed herein are used as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed.

What is claimed is:

1. A sewing machine needle which comprises, a conically shaped leading end portion having a sharp point, a shank portion at the butt end of said needle, a blade portion intermediate said leading end portion and shank portion, an eye at the leading end of said blade portion, said blade portion having elongate flats along each side of said blade portion extending from a locus adjacent the base end of said conically shaped leading end portion to said shank portion, said flats lying in parallel planes and being progressively wider in a direction toward the shank portion, and said blade portion gradually increasing in cross-sectional area from its leading end toward said shank portion, and a thread groove on at least one side of said needle which lies between said flats, said thread groove extending from said eye to said shank portion.

2. A sewing machine needle according to claim 1 in which said blade portion is curved.

3. A sewing machine needle which comprises a conically shaped leading end portion having a sharp point, a shank portion at the butt end of said needle and a blade portion between said leading end and shank portions, said blade portion having an eye at its leading end and flat sides extending from the leading end of said shank to a place adjacent said eye, said flats being wider in vertical direction at their trailing ends than at their leading ends and lying in spaced parallel planes, a constant width thread groove in the top side of said blade extending from the shank to a place beyond said eye, a groove on the underside of said needle extending under said eye,

said blade being larger in cross section at the trailing end of said blade in a plane normal to the axis of said blade than at the leading end of said blade.

4. A sewing machine needle according to claim 3 in which said blade is curved in a direction to place said thread groove on the upper side of said needle along the convex side of the curved blade.

5. A sewing machine needle according to claim 3 in which the underside of said blade has a thread groove at its trailing end, shorter in length than the thread groove on the top side of said blade.

6. A sewing machine needle according to claim 4 having a thread groove on the concave side of said curved blade at its trailing end shorter in length than the thread groove on the convex side.

7. A sewing machine needle according to claim 6 in which the peripheries of the surface portions of the blade between the long edges of said flat side surfaces and the corner edges of said grooves in a plane normal to the long axis of said blade are ovaloid in shape.

8. A sewing machine needle which comprises a conically shaped leading end portion having a sharp point, a shank portion on the butt end of said needle, a blade portion intermediate said leading end portion and shank portion, an eye in the leading end of said blade portion, said blade portion having elongated flats in spaced parallel relation along each side of said blade portion extending from the leading end of said shank to a place adjacent said conically shaped leading end portion, said flats gradually increasing in Width from their leading ends to their trailing ends, the blade portion gradually increasing in thickness and cross sectional area from the conically shaped leading end portion to the shank portion, a thread groove on at least one side of said needle between said flats, said thread groove extending from said eye to said shank portion.

9. For a sewing machine for sewing fabric and the like, a sewing machine needle which comprises a conically shaped leading end portion having a sharp point, a shank portion at the butt end of said needle, a blade portion intermediate said leading end portion and shank portion, said blade portion having elongated flats along each side of said blade portion extending from the leading end of said shank to a place adjacent said conically shaped leading end portion, said flats being wider in vertical direction at their trailing ends than at their leading ends, the blade portion gradually increasing in thickness from the conically shaped leading end portion to the shank portion along the long axis of the blade portion in the plane of symmetry through the hereinafter mentioned thread groove, a thread groove on at least one side of said needle between said flats, an eye in the leading end of said blade portion, said thread groove extending from said eye to said shank portion.

References Cited UNITED STATES PATENTS 357,805 2/1887 Willcox 112-222 1,078,955 11/1913 Reynolds 112-222 1,949,349 2/1934 Brown 1l2-222 FOREIGN PATENTS 1,143,980 4/1959 France.

JORDAN FRANKLIN, Primary Examiner.

R. J. SCANLAN, Assistant Examiner, 

1. A SEWING MACHINE NEEDLE WHICH COMPRISES, A CONICALLY SHAPED LEADING END PORTION HAVING A SHARP POINT, A SHANK PORTION AT THE BUTT END OF SAID NEEDLE, A BLADE PORTION INTERMEDIATE SAID LEADING END PORTION AND SHANK PORTION, AN EYE AT THE LEADING END OF SAID BLADE PORTION, SAID BLADE PORTION HAVING ELONGATE FLATS ALONG EACH SIDE OF SAID BLADE PORTION EXTENDING FROM A LOCUS ADJACENT THE BASE END OF SAID CONICALLY SHAPED LEADING END PORTION TO SAID SHANK PORTION, SAID FLATS LYING IN PARALLEL PLANES AND BEING PROGRESSIVELY WIDER IN A DIRECTION TOWARD THE SHANK PORTION, AND SAID BLADE PORTION GRADUALLY INCREASING IN CROSS-SECTIONAL AREA FROM ITS LEADING END TOWARD SAID SHANK PORTION, AND A THREAD GROOVE ON AT LEAST ONE SIDE OF SAID NEEDLE WHICH LIES BETWEEN SAID FLATS, SAID THREAD GROOVE EXTENDING FROM SAID EYE TO SAID SHANK PORTION. 